Therapeutic pads or packs are often used to warm muscles or reduce cramping. Most conventional pads require the use of external heating or reactants that undergo an exothermic reaction when mixed (i.e., chemical pads). “Bag-in-bag” chemical pads, for example, typically possess a smaller bag containing one reactant that is encompassed by a larger bag containing the other reactant. However, such chemical pads have a large surface area between the first reactant and the second reactant. Thus, the likelihood that the reactants will prematurely migrate through the smaller bag is increased. Although migration may be slowed with thicker materials, this sometimes results in an increased difficulty to rupture the material. Contrary to “bag-in-bag” chemical pads, “side-by-side” pads use a breakable seal that is positioned between two compartments, each of which contains one of the reactants. These pads attempt to use a strong exterior seal around the perimeter of the bag and a weak interior seal between the two compartments. However, this is difficult to achieve on a consistent basis and any rupturing of the exterior seal may cause a leak of the reactants onto the user.
As such, a need continues to exist for therapeutic pads that are easy to use and achieve consisting heating of a desired body part.